Working with Modems

The Modem Manager is a VTS service that enables modems distributed across a number of different workstations to be managed as a common pool. This is accomplished by designating a workstation as a Modem Manager server. The Modem Manager Server and clients cooperate to provide modem pool management and to set up data paths between modem users and the allocated modems. The modem pool is managed using a time priority queue.

Outgoing calls are queued and are then executed at the requested time. You can receive calls on any modems, even on those on backup servers or clients. Call queue information is distributed to all copies of Modem Manager on a networked system so that queue integrity is maintained, even after switching to a backup server. If a call has not yet been established, and server fail-over has occurred, the call will be completed by the backup server that will handle the Modem Manager's preserved queue.

All modem access uses TAPI – the Microsoft telephony management layer that enables programs to share and pass calls. TAPI allows telephony resources to be shared between multiple applications. It interfaces to a modem driver so VTS doesn't have to be configured for the specifics of the modem.

Both a modem audio driver and a TAPI Service Provider (TSP) are provided by Trihedral.  These have been designed to avoid several of the problems associated with the older Unimodem V driver, including its limitation in detecting and switching between voice vs. data calls.

The Unimodem V Driver is still available, but will not display in the list of drivers unless you set the Config.ini variable UseUnimodem to 1.